Twenty-four young adult (age 18-39 years old) survivors of childhood acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL)will be enrolled in a six-month randomized, double-blind (participants and investigators), placebo-controlled pilot clinical trial comparing the effects of atorvastatin versus placebo on endothelial function and other measures of vascular health. Following baseline testing, subjects will be randomly assigned (1:1) to either atorvastatin or placebo. Participants will return at 1-month and 3-months for assessment of safety (blood draw and adverse event assessment) and medication compliance and at 6-months for assessment of safety, medication compliance, and reassessment of baseline variables.